1. Field of the Invention
The present invention generally relates to an earth working implement and more particularly to a grader especially adapted for use in association with a tractor having a three-point hitch with the grader being capable of use in cutting, moving, spreading and leveling all types of soil, aggregate and the like. The grader can also be used to carry, spread and level hot and cold asphalt, soil, aggregate and the like. The grader has blades adjustable to a predetermined depth with the specific angle of the grader blades and the speed of movement in relation to the surface being worked determining the operational characteristics of the grader. The grader includes a pair of transversely extending blades oriented at a particular angle and being vertically adjustably attached to a pair of side frame members having ground engaging slide shoes along the lower surface thereof. The ends of the blades are vertically adjustably connected to the side frame members and provided with manually operated cam structures to adjust the blades vertically. The blades are mounted on an angled support bar in vertically adjusted positions to enable the position of the blades to be adjusted to compensate for wear.
2. Description of the Prior Art
Prior U.S. Pat. No. 4,320,988 issued Mar. 23, 1982 discloses a structure in the form of a grader/spreader which includes blades which can function as grader blades or as a spreader. The prior art cited in the above patent and made of record herein is also relevant to this invention. However, the prior art does not disclose a grader with a rigid blade arrangement which can be adjusted to compensate for wear and to orient the edge of the blade in a predetermined relation to the slide shoes on a pair of side frame members with the blade being supported by a mounting structure in a manner to enable the blade to be adjusted in relation to the mounting structure to compensate for wear and to provide a blade which can be oriented in numerous increments of adjustment to compensate for blade wear to maintain a substantially constant depth relationship between the bottom edge of the grader blades and the bottom surface of slide shoes on the side frame members of the grader. Further, the prior art does not disclose grader blades rigidly associated with side frame members in which the blades are oriented at a 17.degree. angle in relation to vertical to enable the grader blades to be used as a grader with the angle of the blade providing optimum cut into the surface bed while creating a "boiling" effect on the material with the material moving in a rotatable motion due to the angle of the blades with this movement providing optimum mix and distribution of the material back to the surface bed with the fine material being released first to form a base and the larger material then being released to form the top layer on the surface bed thereby providing an ideal mix for compaction. The blades are also used to move material by slowing the tractor or other towing vehicle with the angle of the blades enabling the material to be pulled and distributed. The "boiling" effect causes the material to mix as indicated previously but instead of releasing the material, it rolls in front of the blades until released by the operator by lifting the grader by using the three-point hitch in a conventional manner.